The present invention relates to the area of absorptive sanitary devices, and more particularly to sanitary devices comprising fluid-pervious and fluid-impervious components.
The preparation of sanitary devices has conventionally entailed the provision of an absorbent material in loose or fiberous form which is, in some manner, held together either by a fluid-impervious adhesive or by containment within a shroud comprising a fluid-pervious facing and a fluid impervious backing. Common absorbents comprised short-length cellulosic fibers in the form of bulky masses or compacted thin paper sheets. These materials tended to bunch up or shred upon wetting and caused the wearer great discomfort as well as allowing undesirable leakage or "strike-through" to occur.
In addition to the above varieties of devices, extensive numbers of sanitary products employ what is called a baffle or barrier layer comprising a fluid-impervious sheet or the like which is placed centrally within the product and surrounded with absorbent material on both sides, for the purpose of diverting and equally distributing the flow of fluid throughout the absorbent material. The production of products of this type is expensive, and the results obtained by pads employing baffles are not so improved.
Recently, the use of hydrophilic foam material has been proposed in an effort to obviate some of the prior art difficulties. Specifically, U.S. Pat. No. 3,563,243 by Lindquist, proposes to employ a hydrophilic polyurethane material as the absorbent in a sanitary sheet product. Patentee, however, found that the foams employed therein tend undesirably to change size and shape upon absorption of substantial liquid, and, accordingly, preferred to enclose the foams within backing and facing members, alone or in combination with other foams or cellulose crepe tissue layers.
The use of backing and facing members results in higher product cost resulting from the additional time and effort required to manufacture the devices, and the cost of the starting materials.